From: Yu-cheng Yu <yu-cheng.yu@intel.com>
To: x86@kernel.org, "H. Peter Anvin" <hpa@zytor.com>,
Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>,
linux-kernel@vger.kernel.org, linux-doc@vger.kernel.org,
linux-mm@kvack.org, linux-arch@vger.kernel.org,
linux-api@vger.kernel.org, Arnd Bergmann <arnd@arndb.de>,
Andy Lutomirski <luto@amacapital.net>,
Balbir Singh <bsingharora@gmail.com>,
Cyrill Gorcunov <gorcunov@gmail.com>,
Dave Hansen <dave.hansen@linux.intel.com>,
Florian Weimer <fweimer@redhat.com>,
"H.J. Lu" <hjl.tools@gmail.com>, Jann Horn <jannh@google.com>,
Jonathan Corbet <corbet@lwn.net>,
Kees Cook <keescook@chromiun.org>,
Mike Kravetz <mike.kravetz@oracle.com>,
Nadav Amit <nadav.amit@gmail.com>,
Oleg Nesterov <oleg@redhat.com>, Pavel Machek <pavel@ucw.cz>,
Peter Zijlstra <peterz@infradead.org>,
"Ravi V. Shankar" <ravi.v.shankar@intel.com>,
Vedvyas Shanbhogue <vedvyas.shanbhogue@intel.com>
Cc: Yu-cheng Yu <yu-cheng.yu@intel.com>
Subject: [RFC PATCH v2 26/27] x86/cet/shstk: Handle thread shadow stack
Date: Tue, 10 Jul 2018 15:26:38 -0700 [thread overview]
Message-ID: <20180710222639.8241-27-yu-cheng.yu@intel.com> (raw)
In-Reply-To: <20180710222639.8241-1-yu-cheng.yu@intel.com>
The shadow stack for clone/fork is handled as the following:
(1) If ((clone_flags & (CLONE_VFORK | CLONE_VM)) == CLONE_VM),
the kernel allocates (and frees on thread exit) a new SHSTK
for the child.
It is possible for the kernel to complete the clone syscall
and set the child's SHSTK pointer to NULL and let the child
thread allocate a SHSTK for itself. There are two issues
in this approach: It is not compatible with existing code
that does inline syscall and it cannot handle signals before
the child can successfully allocate a SHSTK.
(2) For (clone_flags & CLONE_VFORK), the child uses the existing
SHSTK.
(3) For all other cases, the SHSTK is copied/reused whenever the
parent or the child does a call/ret.
This patch handles cases (1) & (2). Case (3) is handled in
the SHSTK page fault patches.
Signed-off-by: Yu-cheng Yu <yu-cheng.yu@intel.com>
---
arch/x86/include/asm/cet.h | 2 ++
arch/x86/include/asm/mmu_context.h | 3 +++
arch/x86/kernel/cet.c | 33 ++++++++++++++++++++++++++++++
arch/x86/kernel/process.c | 1 +
arch/x86/kernel/process_64.c | 7 +++++++
5 files changed, 46 insertions(+)
diff --git a/arch/x86/include/asm/cet.h b/arch/x86/include/asm/cet.h
index 71da2cccba16..d5737f3346f2 100644
--- a/arch/x86/include/asm/cet.h
+++ b/arch/x86/include/asm/cet.h
@@ -20,6 +20,7 @@ struct cet_status {
#ifdef CONFIG_X86_INTEL_CET
int cet_setup_shstk(void);
+int cet_setup_thread_shstk(struct task_struct *p);
void cet_disable_shstk(void);
void cet_disable_free_shstk(struct task_struct *p);
int cet_restore_signal(unsigned long ssp);
@@ -29,6 +30,7 @@ int cet_setup_ibt_bitmap(void);
void cet_disable_ibt(void);
#else
static inline int cet_setup_shstk(void) { return 0; }
+static inline int cet_setup_thread_shstk(struct task_struct *p) { return 0; }
static inline void cet_disable_shstk(void) {}
static inline void cet_disable_free_shstk(struct task_struct *p) {}
static inline int cet_restore_signal(unsigned long ssp) { return 0; }
diff --git a/arch/x86/include/asm/mmu_context.h b/arch/x86/include/asm/mmu_context.h
index bbc796eb0a3b..662755048598 100644
--- a/arch/x86/include/asm/mmu_context.h
+++ b/arch/x86/include/asm/mmu_context.h
@@ -13,6 +13,7 @@
#include <asm/tlbflush.h>
#include <asm/paravirt.h>
#include <asm/mpx.h>
+#include <asm/cet.h>
extern atomic64_t last_mm_ctx_id;
@@ -228,6 +229,8 @@ do { \
#else
#define deactivate_mm(tsk, mm) \
do { \
+ if (!tsk->vfork_done) \
+ cet_disable_free_shstk(tsk); \
load_gs_index(0); \
loadsegment(fs, 0); \
} while (0)
diff --git a/arch/x86/kernel/cet.c b/arch/x86/kernel/cet.c
index 8bbd63e1a2ba..2a366a5ccf20 100644
--- a/arch/x86/kernel/cet.c
+++ b/arch/x86/kernel/cet.c
@@ -155,6 +155,39 @@ int cet_setup_shstk(void)
return 0;
}
+int cet_setup_thread_shstk(struct task_struct *tsk)
+{
+ unsigned long addr, size;
+ struct cet_user_state *state;
+
+ if (!current->thread.cet.shstk_enabled)
+ return 0;
+
+ state = get_xsave_addr(&tsk->thread.fpu.state.xsave,
+ XFEATURE_MASK_SHSTK_USER);
+
+ if (!state)
+ return -EINVAL;
+
+ size = tsk->thread.cet.shstk_size;
+ if (size == 0)
+ size = in_ia32_syscall() ? SHSTK_SIZE_32:SHSTK_SIZE_64;
+
+ addr = shstk_mmap(0, size);
+
+ if (addr >= TASK_SIZE_MAX) {
+ tsk->thread.cet.shstk_base = 0;
+ tsk->thread.cet.shstk_size = 0;
+ tsk->thread.cet.shstk_enabled = 0;
+ return -ENOMEM;
+ }
+
+ state->user_ssp = (u64)(addr + size - sizeof(u64));
+ tsk->thread.cet.shstk_base = addr;
+ tsk->thread.cet.shstk_size = size;
+ return 0;
+}
+
void cet_disable_shstk(void)
{
u64 r;
diff --git a/arch/x86/kernel/process.c b/arch/x86/kernel/process.c
index 309ebb7f9d8d..43a57d284a22 100644
--- a/arch/x86/kernel/process.c
+++ b/arch/x86/kernel/process.c
@@ -127,6 +127,7 @@ void exit_thread(struct task_struct *tsk)
free_vm86(t);
+ cet_disable_free_shstk(tsk);
fpu__drop(fpu);
}
diff --git a/arch/x86/kernel/process_64.c b/arch/x86/kernel/process_64.c
index 12bb445fb98d..6e493b0bcedd 100644
--- a/arch/x86/kernel/process_64.c
+++ b/arch/x86/kernel/process_64.c
@@ -317,6 +317,13 @@ int copy_thread_tls(unsigned long clone_flags, unsigned long sp,
if (sp)
childregs->sp = sp;
+ /* Allocate a new shadow stack for pthread */
+ if ((clone_flags & (CLONE_VFORK | CLONE_VM)) == CLONE_VM) {
+ err = cet_setup_thread_shstk(p);
+ if (err)
+ goto out;
+ }
+
err = -ENOMEM;
if (unlikely(test_tsk_thread_flag(me, TIF_IO_BITMAP))) {
p->thread.io_bitmap_ptr = kmemdup(me->thread.io_bitmap_ptr,
--
2.17.1
next prev parent reply other threads:[~2018-07-10 22:31 UTC|newest]
Thread overview: 123+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-07-10 22:26 [RFC PATCH v2 00/27] Control Flow Enforcement (CET) Yu-cheng Yu
2018-07-10 22:26 ` [RFC PATCH v2 01/27] x86/cpufeatures: Add CPUIDs for Control-flow Enforcement Technology (CET) Yu-cheng Yu
2018-07-10 22:26 ` [RFC PATCH v2 02/27] x86/fpu/xstate: Change some names to separate XSAVES system and user states Yu-cheng Yu
2018-07-10 22:26 ` [RFC PATCH v2 03/27] x86/fpu/xstate: Enable XSAVES system states Yu-cheng Yu
2018-07-10 22:26 ` [RFC PATCH v2 04/27] x86/fpu/xstate: Add XSAVES system states for shadow stack Yu-cheng Yu
2018-07-10 22:26 ` [RFC PATCH v2 05/27] Documentation/x86: Add CET description Yu-cheng Yu
2018-07-11 8:27 ` Pavel Machek
2018-07-11 15:25 ` Yu-cheng Yu
2018-07-11 9:57 ` Florian Weimer
2018-07-11 13:47 ` H.J. Lu
2018-07-11 14:53 ` Yu-cheng Yu
2018-07-10 22:26 ` [RFC PATCH v2 06/27] x86/cet: Control protection exception handler Yu-cheng Yu
2018-07-10 22:26 ` [RFC PATCH v2 07/27] x86/cet/shstk: Add Kconfig option for user-mode shadow stack Yu-cheng Yu
2018-07-10 22:26 ` [RFC PATCH v2 08/27] mm: Introduce VM_SHSTK for shadow stack memory Yu-cheng Yu
2018-07-11 8:34 ` Peter Zijlstra
2018-07-11 16:15 ` Yu-cheng Yu
2018-07-10 22:26 ` [RFC PATCH v2 09/27] x86/mm: Change _PAGE_DIRTY to _PAGE_DIRTY_HW Yu-cheng Yu
2018-07-10 22:26 ` [RFC PATCH v2 10/27] x86/mm: Introduce _PAGE_DIRTY_SW Yu-cheng Yu
2018-07-11 8:45 ` Peter Zijlstra
2018-07-11 9:21 ` Peter Zijlstra
2018-07-10 22:26 ` [RFC PATCH v2 11/27] x86/mm: Modify ptep_set_wrprotect and pmdp_set_wrprotect for _PAGE_DIRTY_SW Yu-cheng Yu
2018-07-10 22:44 ` Dave Hansen
2018-07-10 23:23 ` Nadav Amit
2018-07-10 23:52 ` Dave Hansen
2018-07-11 8:48 ` Peter Zijlstra
2018-07-10 22:26 ` [RFC PATCH v2 12/27] x86/mm: Shadow stack page fault error checking Yu-cheng Yu
2018-07-10 22:52 ` Dave Hansen
2018-07-11 17:28 ` Yu-cheng Yu
2018-07-10 23:24 ` Dave Hansen
2018-07-10 22:26 ` [RFC PATCH v2 13/27] mm: Handle shadow stack page fault Yu-cheng Yu
2018-07-10 23:06 ` Dave Hansen
2018-07-11 9:06 ` Peter Zijlstra
2018-08-14 21:28 ` Yu-cheng Yu
2018-07-10 22:26 ` [RFC PATCH v2 14/27] mm: Handle THP/HugeTLB " Yu-cheng Yu
2018-07-10 23:08 ` Dave Hansen
2018-07-11 9:10 ` Peter Zijlstra
2018-07-11 16:11 ` Yu-cheng Yu
2018-07-20 14:20 ` Dave Hansen
2018-07-20 14:58 ` Yu-cheng Yu
2018-07-10 22:26 ` [RFC PATCH v2 15/27] mm/mprotect: Prevent mprotect from changing shadow stack Yu-cheng Yu
2018-07-10 23:10 ` Dave Hansen
2018-07-11 9:12 ` Peter Zijlstra
2018-07-11 16:07 ` Yu-cheng Yu
2018-07-11 16:22 ` Dave Hansen
2018-07-10 22:26 ` [RFC PATCH v2 16/27] mm: Modify can_follow_write_pte/pmd for " Yu-cheng Yu
2018-07-10 23:37 ` Dave Hansen
2018-07-11 17:05 ` Yu-cheng Yu
2018-07-13 18:26 ` Dave Hansen
2018-07-17 23:03 ` Yu-cheng Yu
2018-07-17 23:11 ` Dave Hansen
2018-07-17 23:15 ` Dave Hansen
2018-07-18 20:14 ` Yu-cheng Yu
2018-07-18 21:45 ` Dave Hansen
2018-07-18 23:10 ` Yu-cheng Yu
2018-07-19 0:06 ` Dave Hansen
2018-07-19 17:06 ` Yu-cheng Yu
2018-07-19 19:31 ` Dave Hansen
2018-07-11 9:29 ` Peter Zijlstra
2018-07-17 23:00 ` Yu-cheng Yu
2018-07-10 22:26 ` [RFC PATCH v2 17/27] x86/cet/shstk: User-mode shadow stack support Yu-cheng Yu
2018-07-10 23:40 ` Dave Hansen
2018-07-11 9:34 ` Peter Zijlstra
2018-07-11 15:45 ` Yu-cheng Yu
2018-07-11 9:36 ` Peter Zijlstra
2018-07-11 21:10 ` Jann Horn
2018-07-11 21:34 ` Andy Lutomirski
2018-07-11 21:51 ` Jann Horn
2018-07-11 22:21 ` Andy Lutomirski
2018-07-13 18:03 ` Yu-cheng Yu
2018-07-10 22:26 ` [RFC PATCH v2 18/27] x86/cet/shstk: Introduce WRUSS instruction Yu-cheng Yu
2018-07-10 23:48 ` Dave Hansen
2018-07-12 22:59 ` Yu-cheng Yu
2018-07-12 23:49 ` Dave Hansen
2018-07-13 1:50 ` Dave Hansen
2018-07-13 2:21 ` Andy Lutomirski
2018-07-13 4:16 ` Dave Hansen
2018-07-13 4:18 ` Dave Hansen
2018-07-13 17:39 ` Yu-cheng Yu
2018-07-13 5:55 ` Andy Lutomirski
2018-07-11 9:44 ` Peter Zijlstra
2018-07-11 15:06 ` Yu-cheng Yu
2018-07-11 15:30 ` Peter Zijlstra
2018-07-11 9:45 ` Peter Zijlstra
2018-07-11 14:58 ` Yu-cheng Yu
2018-07-11 15:27 ` Peter Zijlstra
2018-07-11 15:41 ` Yu-cheng Yu
2018-07-13 12:12 ` Dave Hansen
2018-07-13 17:37 ` Yu-cheng Yu
2018-07-10 22:26 ` [RFC PATCH v2 19/27] x86/cet/shstk: Signal handling for shadow stack Yu-cheng Yu
2018-07-10 22:26 ` [RFC PATCH v2 20/27] x86/cet/shstk: ELF header parsing of CET Yu-cheng Yu
2018-07-11 11:12 ` Florian Weimer
2018-07-11 19:37 ` Jann Horn
2018-07-11 20:53 ` Yu-cheng Yu
2018-07-10 22:26 ` [RFC PATCH v2 21/27] x86/cet/ibt: Add Kconfig option for user-mode Indirect Branch Tracking Yu-cheng Yu
2018-07-10 22:26 ` [RFC PATCH v2 22/27] x86/cet/ibt: User-mode indirect branch tracking support Yu-cheng Yu
2018-07-11 0:11 ` Dave Hansen
2018-07-11 22:10 ` Yu-cheng Yu
2018-07-11 22:40 ` Dave Hansen
2018-07-11 23:00 ` Yu-cheng Yu
2018-07-11 23:16 ` Dave Hansen
2018-07-13 17:56 ` Yu-cheng Yu
2018-07-13 18:05 ` Dave Hansen
2018-07-11 21:07 ` Jann Horn
2018-07-10 22:26 ` [RFC PATCH v2 23/27] mm/mmap: Add IBT bitmap size to address space limit check Yu-cheng Yu
2018-07-10 23:57 ` Dave Hansen
2018-07-11 16:56 ` Yu-cheng Yu
2018-07-10 22:26 ` [RFC PATCH v2 24/27] x86: Insert endbr32/endbr64 to vDSO Yu-cheng Yu
2018-07-10 22:26 ` [RFC PATCH v2 25/27] x86/cet: Add PTRACE interface for CET Yu-cheng Yu
2018-07-11 10:20 ` Ingo Molnar
2018-07-11 15:40 ` Yu-cheng Yu
2018-07-12 14:03 ` Ingo Molnar
2018-07-12 22:37 ` Yu-cheng Yu
2018-07-12 23:08 ` Thomas Gleixner
2018-07-13 16:07 ` Yu-cheng Yu
2018-07-13 6:28 ` Pavel Machek
2018-07-13 13:33 ` Ingo Molnar
2018-07-14 6:27 ` Pavel Machek
2018-07-10 22:26 ` Yu-cheng Yu [this message]
2018-07-10 22:26 ` [RFC PATCH v2 27/27] x86/cet: Add arch_prctl functions " Yu-cheng Yu
2018-07-11 12:19 ` Florian Weimer
2018-07-11 21:02 ` Yu-cheng Yu
2018-07-11 19:45 ` Jann Horn
2018-07-11 20:55 ` Yu-cheng Yu
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